The present invention relates to electric toothbrush mechanisms. More particularly, although not exclusively, the invention relates to a replaceable brushing attachment for an electric toothbrush, having a tuft block that is moved reciprocally by a rotating crankshaft.
There are many known electric toothbrush mechanisms having pivotally oscillating tuft blocks. Some such mechanisms are known to include a pivotally oscillating circular tuft block that oscillates back and forth about an axis that extends parallel to the bristles. The centre-most bristles of such tuft blocks provide little, if any cleaning action.
Other electric toothbrushes are known, which comprise a bristle head that moves reciprocally back and forth in a direction parallel to the longitudinal axis of the toothbrush. Such a toothbrush is disclosed in U.S. Pat. No. 4,995,131. This type of bristle movement has been criticised as being inefficient, as the bristle tips move along the gum line, instead of across the gum line.
U.S. Pat. Nos. 4,149,291 and 5,253,382 each disclose electric toothbrush mechanisms having a pivotally oscillating brushing head. In these arrangements, the entire neck of the toothbrush and the brush head itself must pivot back and forth about a pivot axis. These devices are cumbersome, inefficient and uncomfortable to use.